The Parliament of the United Kingdom of Great Britain and Northern Ireland[1] (commonly referred to as the British Parliament, the Westminster Parliament or, formerly, the Imperial Parliament) is the supreme legislative body in the United Kingdom and British overseas territories, located in London. Parliament alone possesses legislative supremacy and thereby ultimate power over all other political bodies in the UK and its territories. At its head is the Sovereign, Queen Elizabeth II.

The parliament is bicameral, with an upper house, the House of Lords, and a lower house, the House of Commons.[2] The Queen is the third component of the legislature.[3][4] The House of Lords includes two different types of members: the Lords Spiritual (the senior bishops of the Church of England) and the Lords Temporal (members of the Peerage) whose members are not elected by the population at large, but are appointed by the Sovereign on advice of the Prime Minister.[5] Prior to the opening of the Supreme Court in October 2009 the House of Lords also performed a judicial role through the Law Lords. The House of Commons is a democratically elected chamber with elections to it held at least every five years.[6] The two Houses meet in separate chambers in the Palace of Westminster (commonly known as the Houses of Parliament), in London. By constitutional convention, all government ministers, including the Prime Minister, are members of the House of Commons or, less often, the House of Lords, and are thereby accountable to the respective branches of the legislature.